A variety of metal thin films have been widely used up to the present in various electronic devices such as resistors, electrodes and sensors. Among the metal thin films, those of noble metals can be easily produced by vacuum technologies including spattering and vacuum deposition as well as by coating followed by thermal decomposition of precious metal resinates. As to base metal thin films, however, application of vapor technology has been the sole means for their production. Although preparation of base metal thin films by means of plating has been studied in certain cases, it has been difficult to obtain a thin film having the thickness of 1 .mu.m or thinner which has a uniform thickness over a wide area of the thin film by such means. Further, a method for preparing a base metal thin film is known which comprises by forming an organometallic compound layer on a substrate and then heat treating said layer in an inert gas or reductive atmosphere [cf. for example, Solid State Technology, February, p.p. 49 (1974)], but such method has the disadvantage of leaving carbon residue in the resulting film.
The above-mentioned prior art methods for producing metal thin film by using vacuum technology have a number of problems, thus, such methods require an expensive production apparatus, also, they are poor in productivity because they are run by batch-wise production process. Further, thin film having large area can hardly be produced, because such method require a vacuum vessel.